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Proceedings Paper

Photometric flats: an essential ingredient for photometry with wide-field imagers
Author(s): Fernando J. Selman
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Paper Abstract

We discuss the challenges to photometry introduced by internal redistribution of light in wide-field imaging cameras with focal-reducers. We have developed a simple least-squares procedure which can be used to determine the zero-point variations across the field. The method uses three orthogonally offseted images of a reasonably dense stellar field, plus an image containing at least three standard stars scattered across the field. The method, which does not require rotating the instrument, have been applied to correct data from the Wide Field Imager at La Silla. It has been shown to reduce a 12% center-to-edge gradient down to a ~2% rms variation accross the field. A new method which can be used with data taken during non-photometric nights is also presented.

Paper Details

Date Published: 16 September 2004
PDF: 7 pages
Proc. SPIE 5493, Optimizing Scientific Return for Astronomy through Information Technologies, (16 September 2004); doi: 10.1117/12.551357
Show Author Affiliations
Fernando J. Selman, European Southern Observatory (Chile)


Published in SPIE Proceedings Vol. 5493:
Optimizing Scientific Return for Astronomy through Information Technologies
Peter J. Quinn; Alan Bridger, Editor(s)

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